kth number in range

#include <bits/stdc++.h>
#define x first
#define y second
#define pii pair<int,int>
#define pb push_back
#define all(a) begin(a),end(a)

using namespace std;

const char en='\n';
const int N=100010,M=1<<17;
int q,n,h[N],nod[N],cn[N],seg[M*2],req[N];
vector<pii> qu[N];

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin>>n>>q;
    vector<int> v;
    for (int i=0;i<n;++i)
    {
        cin>>h[i];
        v.pb(h[i]);
    }
    sort(all(v));
    v.erase(unique(all(v)),v.end());
    for (int i=0;i<n;++i) h[i]=lower_bound(all(v),h[i])-v.begin();
    for (int i=0;i<q;++i)
    {
        int a,b,c;
        cin>>a>>b>>c;
        --a;
        qu[a].pb({i,-1});
        qu[b].pb({i,1});
        nod[i]=1;
        req[i]=c;
    }
    int off=2,st=M/2;
    while (off<=M)
    {
        memset(cn,0,sizeof(cn));
        for (int i=0;i<q;++i) nod[i]*=2;
        for (int i=0;i<=n;++i)
        {
            for (auto a: qu[i]) cn[a.x]+=a.y*seg[nod[a.x]];
            if (i<n) ++seg[off+h[i]/st];
        }
        for (int i=0;i<q;++i) if (cn[i]<req[i]) ++nod[i],req[i]-=cn[i];
        off*=2,st/=2;
    }
    for (int i=0;i<q;++i) cout<<v[nod[i]-M]<<en;
}